As noted, pasted nickel hydroxide electrodes can have their performance improved by the addition of conductive diluents to improve active material utilization, and such as to establish a conductive insoluble CoOOH network in situ within a pasted nickel hydroxide electrode.
However, the problem of low positive electrode efficiency is exacerbated, sometimes significantly, when their use in nickel zinc batteries is considered, because of the electrolyte requirements of the zinc electrode.
Of course, it is well known that performance inhibiting disfigurement or rearrangement of zinc electrodes can occur during the cycling process of rechargeable zinc electrodes in alkaline electrolytes. Such disfigurement can be minimized in more dilute alkali hydroxide solutions.
The Jones Patent, noted above, appears to be somewhat effective in extending cycle life of the cell by the addition of calcium hydroxide to the zinc electrode.
It has also been noted that buffered electrolytes with or without fluoride additions may also result in increased zinc electrode lifespan. They are particularly described in the Adler et al patent, noted above, where a mixture of alkaline electrolyte having a strength of 2M to 12M is combined with a carbonate of 0.5M to 4M, and a fluoride of 0.5M to 4M.
The Carlson Patent, noted above, describes a mixture that employs 5% to 10% of hydroxide, 10% to 20% of phosphate, and 5% to 15% of fluoride.